Scuff resistant sliding member

ABSTRACT

A sliding member, such as a piston ring or cylinder liner, has a scuffing and abrasion resistant surface layer produced by spraying Fe3O4 on the surface of the base body for the sliding member.

United States Patent Nakamura 1 Aug. 19, 1975 [54] SCUFF RESISTANT SLIDING MEMBER 3,503,775 3/1970 Austin 117/31 3,542,114 11/1970 Ferree et a1. 164/74 175] Inventor YSmkats Nakamura Yokohama 3,549,357 12/1970 Osborne 117/31 Japan 3,632,368 1 1972 1961566 117/16 t a 3,644,133 2/1972 Nelson 1 117/16 3 1 [7 Asslgnee ilppon Plston Ring (,0 Ltd "loky 3,646,993 3/1972 Rice et a1 277/235 A 3,661,402 9 1973 117.6161 .1 277 235 R 22 Filed; 4 1972 3,671,047 6/1972 Umezawa 277/235 R 3,697,091 10/1972 Prasse et a1. 277/235 A 1 1 pp Flo-1311,6111 3,731,941 /1978 Mori 611 111.... 277/235 R 1 3,762,010 /1973 lizuka 29/1566 [30] Foreign Application Priority Data OTHER PUBLICATIONS Dec. 4, 1971 Japan 46-97590 Chemical Abstracts, Vol. 53, p. 13567-f.

Nature of the Wear and Friction of Mild Steel on [52] US. Cl 277/235 A; 164/72; 164/74; Steel, and The Effect of Surface Oxide and Sulfide 29/1566; 277/235 R; 427/34; 428/469 Layers, Piggott et al., Proc. Conf. Lubrication & [51] Int. Cl B051) 7/14; B05b 5/00 Wear, Inst. Mech. Eng, London, 1957, p. 137. [58] Field of Search 117/16, 31, 49,

164/74, 72; 29/1566; 277/235 A, 235 R Primary Examiner-Norman G. Torchin Assistant Examiner-Edward C. Kimlin [56] References Cited Attorney, Agent, or FirmSug11rue, Rothwell, Mion,

UNITED STATES PATENTS Zinn and Macpeak 2,622,993 12/1952 McCullough et a1. 117/49 2,914,480 11/1959 Hagopian 252 6254 [57] ABSTRACT 2,919,486 1/1960 Banquarel 29/1566 A sliding member, such as a piston ring or cylinder 3 12/1967 urhp y et 117/16 liner, has a scuffing and abrasion resistant surface 313611562 H1968 Ulnch aim 117/31 layer produced by spraying Fe O on the surface of 3,364,547 1/1968 Prasse 29/1566 the base body for the Sliding member. 3,421,198 l/l969 Prasse 29/1566 3,473,943 10/1969 Kai et a1. 117/16 2 Claims, 1 Drawing Figure N G) (D I I I l 1 J AUG 9! FATENTEU 1 97a 3,900,200

THE AMOUNT OF WEAR w NO.| No.2 7

SCUFF RESISTANT SLIDING MEMBER BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION This invention relates to an improvement in a sliding member required to have excellent scuffing and abrasion resistance such as a piston ring or cylinder liner for an internal combustion engine.

2. DESCRIPTION OF THE PRIOR ART It is well known to provide a plurality of peripheral grooves on the outer periphery of the piston ring, and to fill a mixture composed of Fe O powder and sodium silicate as the binder in said grooves and then thermoset the filler material in the grooves by heating. This process is intended to improve the scuffing and abrasion resistance of the piston ring, and the thus obtained piston ring is designated as ferrox insert ring.

The ferrox insert ring can be used safely under such severe conditions as often causes scuffing, since the lubricating oil impregnated in the ferrox insert part reduces the friction between the piston ring and cylinder. This piston ring, however, can not keep its scuffing and abrasion resistance for long periods of time, since the binding force of the sodium silicate is not so strong and the hardness of the filler material as the whole is not so high.

On the other hand, the ferrox treatment to improve the break-in property between the piston ring and the cylinder is also known, which is characterized by forming a film of Fe O on the outer periphery of the piston ring. This Fe O film, however, is very thin and will be removed from the piston ring surface during the break in period before the piston ring is subjected to the normal operating conditions. Accordingly, this piston ring is not durable for long usage.

Therefore, this invention is intended to eliminate the above said defects of the conventional piston rings and to provide an improved piston ring having favorable scuffing and abrasion resistance, far better than that of the conventional piston rings by making use of the excellent abrasion resisting property of the Fe O particles.

SUMMARY OF THE INVENTION The feature of this invention is to form a scuffing and abrasion resistant Fe O layer on a surface of a base body for a sliding member, such as a piston ring or cylinder liner, by a metal spraying process. The F e particles are preferably sprayed under plasma heat but may be sprayed with other heat sources.

As the fine Fe O particles are sprayed on the surface of the base body of the sliding member with extremely high velocity, they stick fixedly to the base body surface. The hardness of the sprayed layer is very high so as to even reach Hv (30) 700. Besides, the sprayed layer can be impregnated with the lubricating oil therein due to its porosity. Accordingly, the Fe O sprayed layer exhibits favorable abrasion resistance, lasting oil keeping property, and excellent scuffing resistance.

Now, more particular embodiments of this invention will be described with reference to the following Example and drawing.

BRIEF EXPLANATION OF THE ACCOMPANYING DRAWING The single FIGURE shows the abrasion value of a piston ring specimen No. 2 according to this invention and that of the conventional piston ring. Specimen No. 1 has an M0 sprayed sliding surface, the sprayed surface layer being 0.2 mm in thickness. Specimen No. 2 is a piston ring of this invention having an Fe O sprayed surface layer of 0.1 mm thickness.

EXAMPLE Pure Fe O particles were plasma-sprayed on an outer peripheral surface of the cast iron piston ring composed of TC 3.5 percent, Si 2.6 percent, Mn 0. 6 percent and Fe balance to form a sliding layer having 0.1 mm thickness under following spraying conditions. The Hv (30) hardness of the resultant sprayed layer was 700.

Spraying gun used; Meteco 3 M type plasma-spraying gun N gas pressure; 50 lb/in N gas flow volume; 150 l/hr. H gas pressure; 50 lb/in. H gas flow volume; 10 l/hr. Electric current; 500 A Distance between the spraying gun and the base body surface; 4 in.

The piston ring having the lFe O sprayed layer thus obtained and the conventional piston ring obtained by plasma-spraying a Mo layer having 0.2 mm thickness were subjected to the actual engine test to examine their abrasion resistance under the following conditions.

The test results are shown in the FIGURE, in which the No. 1 specimen is a conventional piston ring having the sprayed layer of M0 percent with the thickness of 0.2mm, and the No. 2 specimen is the piston ring of this invention having the sprayed layer of Fe O 100 percent with the 0.1 mm thickness.

It will be understood from the test results that the abrasion amount of the specimen No. 2 is less than l/3 of that of the specimen No. 1 and the latter is well resistant to the abrasion.

As particularly mentioned above, the sliding member of this invention has the sliding surface which exhibits both excellent scuffing and abrasion resistances.

While this invention has been described with reference to particular embodiments thereof, it will be understood that the numerous modifications may be made by those skilled in the art without actually departing from the scope of the invention. Therefore, the appended claim is intended to cover all such equivalent variations as coming. the true spirit and scope of the invention.

ness of approximately 700 and being of approxi mately 0.1 mm in thickness. I

2. The piston ring as claimed in claim 1, wherein said cast iron base body is composed of 3.5 percent T. C.,

5 2.6 percent Si, 0.6 percent Me and the balance Fe, by

weight, and wherein said F0 0 layer comprises a heat plasma sprayed layer. 

1. A POISTON RING HAVING SCUFFING AND ABRASION REISTANT SLIDING SURFACE LAYER, SAIC PISTON RING COMPRISING: A CAST IRON BODY AND A HOT METAL SPRAYED FE3O4 PARTICLE LAYER ON THE SLIDING SURFACE OF THE CAST IRON BASE BODY, SAID HOT METAL SPRAYED
 2. The piston ring as claimed in claim 1, wherein said cast iron base body is composed of 3.5 percent T. C., 2.6 percent Si, 0.6 percent Mc and the balance Fe, by weight, and wherein said Fe3O4 layer comprises a heat plasma sprayed layer. 